Collax Business Server is an all-in-one Linux server for small- and medium-sized businesses. It delivers all the important network services within a heterogeneous business environment for communication, infrastructure, compliance, groupware, and storage, all in a reliable and secure way which is easy to manage. It also provides essential security functions such as firewalling and virus and spam filtering, to protect against hacker attacks, viruses, and unsolicited email messages.

Hiawatha is a secure and advanced Web server for Unix. It has been written with security as its main goal. It features advanced access control, prevention of SQL injection and cross-site scripting, banning of clients who try such exploits, the ability to run CGIs under any UID/GID you want, and many other features. These features make Hiawatha an interesting Web server for those who need more security than what the other available Web servers are offering. Hiawatha is also fast and easy to configure.

Zentyal Server aims at offering small and medium businesses (SMBs) a native drop-in replacement for Windows Small Business Server and Microsoft Exchange Server which can be set up in less than 30 minutes and is both easy to use and affordable.

QtWebApp allows you to write standalone Web server applications in C++ as easily as Java Servlets. The HTTP 1.1 server supports persistent connections, sessions with cookies, and file uploads. It contains a template engine and a logger that can be configured at runtime. The application runs on Unix as a daemon, on Windows as a service, and on all operating systems on the command line. It is based on Nokia QT 4.7.
Compatibility with QT 4.8 and 5.0 has been verified successfully.

LilacServer is a Web developed in Java that employs Java NIO technology. It is fast and highly productive. It is also a template engine with its own language for creating templates and a framework with its own API.
More features of interest: built-in support for databases via JDBC; integrated localization facilities; sophisticated caching capabilities; support of sessions, multi-part forms, and file uploads; support of third-party libraries; a Web-based management interface; and so on.